Ido not have shape or volume. you cannot see me, but i fill any container in which i am placed. i have weight, but you cannot hold me. what am i?

Which is the best paraphrase of the text? the capability of a bicycle makes some people want to go very fast and others to go very slow. as long as you are careful, feel free to ride like the wind. when feeling brave on a bicycle you should ride fast, but when feeling afraid riding slow is wise. if you are unable to coast, it is pointless to even ride. if you’re going to ride a bicycle, you should throw caution to the wind and take over the road, swerving where you like and taking full advantage of your ride. it’s a real joy to be able to ride a bicycle, where you have the choice of going as fast or as slow as you like, using as much courage as you feel like using.